Catalytic alkylation process for the manufacture of high antiknock gasoline



Mayl, 1948. Q 1 @CON ET AL 2,441,249

CATALYTIC ALKYLATION PROCESS FOR THE MANUFACTURE oF HIGH ANTIKNOCKGASOLINE Filed June 27, 1940 .ujpmm 9.596.

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'pentane :for suitable operation Patented May 11, 1948 CATALYTICALKYLATION PnooEss Fon THE MANUFACTURE OF HIGH ANTI- KNOCK GASOLINECecilio L. Ocon and Ernest A. Ocon, Yonkers,

N. Y.; said Ernest A. Ocon Cecilio L. Ocon assigner to said ApplicationJune 27, 1940, Serial No. 342,812

This invention relates to a process for the manufacture of highanti-knock gasoline by the alkylation of isoparalns, such as isobutane,with olene hydrocarbons such as propene, butene and pentene, in thepresence of a suitable acidic catalyst such as concentrated sulfuricacid.

Among the objects of the present invention is to provide a method forthe economical process ing of normally gaseous olenes and isoparaffinsto give high yields of normally liquid hydrocarbons boiling in thegasoline range, said liquid hydrocarbons being superior-quality blendingagents for aviation gasoline. This object, among others, will becomeapparent as the invention is described.

The hydrocarbon materials for subjection to treatment in this inventionare commonly available in petroleum refineries from various sources,such as a cracking still stabilizer overhead. These renery hydrocarbonfractions, which are most suitable for treatment, contain the followinghydrocarbons: propane, butenes, isobutane, normal butane, pentene,isopentane and normal However, limited amounts of propene may be reactedsuccessfully under substantially the same conditions.

In order to make the invention more fully understood, reference will nowbe made to the accompanying drawing, which is a diagrammaticillustration of one form of apparatus employed of this invention.

Hydrocarbons of suitable composition, such as described above, are drawnfrom a suitable reiinery source I, through line 2, and pumped by pump 3through line 4, wherein they may be joined, if desired, by hydrocarbonrecycle streams passed'through line 5. This mixture is cooled inexchanger 6 and passed through line 1 to reactor 8 jointly with acidrecycle carried in line 9, fresh acid pumped by pump I- through line Il,and a reactor recirculating hydrocarbonacid emulsion pumped by pump I2through line I3. The mixed acid and hydrocarbons are violently agitatedby suitable means (not shown) in the reactor, at temperatures in therange of' F. to '70 F., and at subatmospheric, atmospheric orsuperatmospheric pressures, the pressures employed Ybeing commensuratewith the temperature and composition of the yreactor contents. To alarge degree the agitation is' effected by ebullition, but this may besupplemented by mechanical means (not shown).

The temperature of the reactor 8 is maintained at the desired level byAmeans of allowing a portion of the reactor hydrocarbons to vaporizefrom 's' claims. (o1. 26o-esas) the reactor 8 and pass as vapor throughline I4 to a liquid trap I5, Where entrained liquid and some condensateseparate leaving the vapors to flow through line I6 to compressor I'I,Where the vapors are compressed and ow through line I8 to cooler I9,where the vapors arecooled and condensed. The liquid from the cooler I9passes through line 20 to accumulator drum 2l. A portion of thecompressor condensate liquid is pumped by pump 23 through line 24 todepropanizer tower 25. The propane concentration in the reaction zone iscontrolled through the feed stock composition the rate of charge, andthe rate of recycling used for eliminating the excess propane, which iswithdrawn in the overhead product tail gas from the depropanizer throughline 25. The hydrocarbon depropanizer bottoms having a restricted ornegligible content` of propane flow through line 21, Water cooler 28 andline 29, to join with line 5 and flow back to the reactor.

In the preferred mode of operation for obtaining optimum temperaturecontrol and optimum alkylate yield, the catalyst concentration anddilution of reactants-are controlled vwithin specific limits so as toprevent the formation of undesired =byproducts such as polymers, neutralesters, and oxidized products'. With the alkylation reaction temperaturekept within the optimum range of +20 F. to -|-'70 F., the sulfurie acidstrength is preferably maintained in the range of about 88% to 100%,while the volatile diluent concentration of hydrocarbons, such aspropane and butane, as well as the concentrations of the olefine andisoparaiiin reactants, are maintained Within appropriate limits usingthe 'type of system described. Various metal salts, such as salts ofsilver, copper, vanadiumW-rg"` and mercury, preferably their sulphateaorsimilar salts of strong mineral acids, may be added as promoters. It hasbeen found that boron fluoride can also be used as a promoter foralkylation and also for increasing yields.

Accordingly, the desired efficient temperature control and ahighly-eilcent mixing of the materials in the alkylation zone areobtained by maintaining therein controlled concentrations of highlyvolatile non-reactive hydrocarbons, which undergo vaporization in thereactor under suitable pressures.

More specifically, it is very advantageous to have present in thereaction mixture being subjected to alkylation a small concentration ofpropane in the range of about 1% to 10% by volume of the totalhydrocarbons, and preferably as near pressure in the reactor per squareinch, gage,

occur in all parts of the reaction mixture to prevent stratication andthereby-givingf'addedagitation to the mechanical purposes. Moreover, theinternal cooling is more sensitive to sudden temperature increases thancooling by heat exchange, and permits uniform control with automatictemperature devices;

Thus, the pressure release valve Ito in vapor line-:|54 mayrbethermostaticallly controlledgtand likewise 'the' compressor il, tomaintain. vautomatically the necessary pressure Vin'thereactor forkeeping the aikylationtemperature completely under zcontrol. Forexample,1if=the temperature inthe` reactor` begins' to rise, thevalve-:I onand thecompressor ITzare 'ad'justedi tov decrease thepressure and .lower 'the' temperature inthe` reactorthroughincrea'sed-Vaporizationlcaused therein; :It'will' be. apparentthat ,not any' small amounts of any unreact'edz propen'e, thane, 'and'.Vethylene which may beipresentinthereaction mixture will tendto'lvaporiz'e VWith the.l propane, as lwellias butanesg. i However, thevaporized vhydrocarbons having no :m'orethanv three lcarbon .atoms.other than' 'propane are'ordinarily` present in negligible amounts oflesslthanlb byA volume;..and the vaporized butanes :flowing withApropanevapors'from` the reactor reach :substantial Vproportionsi whenthe temperature ofthe reaction approaches the higher limit of the rangeor if the propane-:concentration becomes very low and thepressure'becomesgreatly decreased-.inthe reactor.'` An additional'advantage' gained from the A'use Bof .propane irifth efmanner.Ydescribedis in .maintaininghigher concentrations of isobutane'rfortherreaotor. Y

Llhe portion of the compressorcondensateliquid,V wiiich icy-passes' thedepropanizer, flows-through line 221th join'withzline for return `to thereactor with the fresh' charge andother recycle streams. "llhesnetliquid hydrocarbon reactor eiuents With-sul'furicacid-r catalyst lpassA'from the reactor 8E .through linek 3 n" to the .acidffsettler drum 3l,wherein the hydrocarbonsareseparated fromi the acidcoatalyst'. Thesulfuric acid catalystxwhich' separates; flows .through line 32. ztopump 33;

thxioughlines 34 andSIasiacid recyclefback :topline- 'iandthenLreturnedto'th'e reactor. i Aquantity ofV usedl sulfuric' acidcatalyst is: withdrawn through lirici-34 tofthe final acid settler S5,where-"anyen'- trained ordissolvedhydrocarbonsare removediby heating theacid.V This usedori spent'acidxflows through line 36 to acid'.sludgestorage-or to an acid recovery'unit forrevivifioation (not shown);

' 'The-'hydrocarbons 'from .the :acidsettler '3| 110W. cmerithe;bailleAplate 'zthroughzline :3:1 toi-'pump 3B; fw-hichr; pumps the.hydrocarbonslV which' Vcon-- tainfithe high" anti-knock' gasoline aswellas. 'the lighter hydrocarbons such as propane, isctiutane;l normal;butano, isopentane,v etc., through line 139 tol 'then-exchanger 'Swherein these'icooler'flrydrofcarbons fseive to reduce:'thertemperaturero'fz .the hizdrccarbonswhich/ lea. .ef-the 1:.. The'hydrocarbons fromfthefacid settler .ow

the. .boiliruggpropane,4 isobutane and normal butane, forthisboilingmay' devices' used. lfo'r such are separated from the caustic `l 4 fromthe exchanger 6 through line 40 to causticwash mixing nozzles 4 I, wherethey are thoroughly contacted with suitable-strength caustic solutionbeing circulated through line 42 by pump 43. The combined caustic andhydrocarbon emulsion filows from'. theemixing .nozzlesi41-lv throughline 44 tcacaustie :settler 45, :Where ,the hydrocarbons, freed of anyacid gases or acid by neutralization,

solution.

.The hydrocarbons flow from the caustic settler drum-:throughline 46 tothe isobutane frac- LtioraatDrM'TI-,Mhere the highly-concentratedisobutioni consisting: :of

tane fraction, Which is taken as net overhead, is

Arecycled.Jtlroughline-i5 to line 4 and back to the reaction system withthe other streams described above; The bottoms materials from theisobutane Vtractionator 47, which contains the bulk of the normalbutanes and the reaction prod- ;uctsfpassfrom the isobutane fractionatorbottom through line 48 to the .debutanizer fractionator 49,;Wherezsubstantially allr ofV the :normali butanes areremoveddoverhead-as-fa .net product .through line.'- 50;Thevbottohrs-imaterial from' the debutanizer flow V:through line '5i':to rerun` fractionatorl 2,' Where;thereactionlproduct'oralkfylate isfractionatediintoianfaviationfraction' which is removed: overheadaasfaproduct through' line .53 and-a- :h'eavier vboiling fraction;.which issuitable for blending-with motor fuel, is removed? 'as a bottomsfproductthroughfli'n'e :54.

'It is,. 4of course; obvious" thatfall references 'to fraotionator'tower :appurtenances 'such as' r ux lzmn'densers',.. pumps, freboilers.valves. etc., havebeenfpurposely omitted `:from this .description, butthe scope of this invention inc'lude's` all suchitems' .andiinstrunientsnecessary 'for the proper "operation .of .alli apparatus, even: though'thesezitems-.areinot specificallyv shown'in the drawing. or 1mentionedinthe'd'escription.

rAsianrillustration of; theioperati'on of ithis 'in- Vention fa;fhydnocarbon:.stockV of the :following constituentsA`isse'lec'tedtasfindicative .ofl a suitable chargef material. (In theyfollowingtabl'e 'the term ibblsf':isiunderstoodto consist of 42U. 'S

'Thez'abov' liqueed .oh'arge `is subjected to treatment?. withrsulfuricl acid catalyst 'of'. 96% s'trengthatra-rtemperature of 40" F.Highly concentratedizisobutane .'liqnid 'is added-y to 'the reeacton'anixture: in?fsuilcientfamountsxto bring the ratio -ofzisobutancio:olenes in'ft'he .reactor to 4'- to` lor higher. fhhereaction productstogether with 4unrearitedlhydrocarlrio'ns'are :separatedA fromv acidoatalystandthe.hydrocarbons washed` lwith caustic: solution' 'to removelany traces .of `acidl gasesf orentrained .sulfuric acid. The'neutralized hydlnbarbons .are ltheir.fractionat'ed into` a .irac-:normally :liquid' Yhigh anti knock'hydrncarbons- :boiling: :in lthegasoline range;. :at highly .concentrated isobutane: .liquidv`fraction-@whiskers returned' to :the-reactor as recycleahighly.'.concentratednormalrzbutane: as: a'. liquid. product-riorblendinggzfandza :propane-rich' turilagas` product. The- .fraction which-c'ons'ists oir-the hi'ghoanti-knock .normally liquidhydrocarbbnsfmay':be: .further :fractionated "into .an

aviation gasoline-blending fraction and a heavier motor fuel fraction.The products derived from the charge stock tabulated above are asfollows:

The foregoing illustration is only one method of operation. Althoughdesigned most advantageously for a continuous operation, the presentprocess may also be adapted for an improved batch operation. It isevident that many modications and variations of this invention may bemade without departing from the scope of the invention.

It is to be understood that instruments for measuring and controllingtemperatures, pressures, and iiow velocities, and also that pumps,compressors for impelling the fiow of fluids through conduits, and othercontrol apparatus not shown or indicated, are to be used for theoperation described when required and in a manner as well known in thelart.

It is also to be understood that this invention is not to be limited bytheoretical considerationsY or specific illustrative examples used forpurposes of illustration, but it is desired to claim all the inventionin the broadest scope in the following claims.

Having described our invention, what we@ claim and desire to secure byLetters Patent is as follows:

1. A continuous alkylation process for the production of normally liquidhydrocarbons of high anti-knock quality boiling in the gasoline range,which comprises subjecting under pressure in a reaction zone normallygaseous hydrocarbons in a liquid phase comprised chiefly of isoparafnsand olenes to the action of strong sulfuric acid catalyst and boronfluoride in the presence of a controlled liquid propane concentrationrestricted to from 1.0 to 10.0% by volume of the hydrocarbons in saidreaction zone.

2. A continuous process for the manufacture of high anti-knock gasoline,which comprises subjecting under pressure in a reaction zone normallygaseous hydrocarbons in a liquid phase comprised chiefly of isobutane,normal butane and butenes in the presence of a controlled liquid propaneconcentration restricted to from 1.0 to 10.0% by volume of thehydrocarbons, to the action of strong sulfuric acid catalyst and boronfluoride in said reaction zone, wherein the isobutane is alkylated bythe butenes to produce normally liquid hydrocarbons of high octanenumber boiling in the gasoline range.

3. In a process for producing gasoline motor fuel from normally gaseoushydrocarbons, the step of reacting isobutane with a normally gaseousolen of at least three carbon atoms per molecule in the presence of acatalyst consisting predominantly of a mixture of sulphuric acid andboron fluoride.

4. In a process for producing motor fuel from a hydrocarbon mixturecontaining an olefin and an isoparafn by treatment with sulfuric acidunder alkylating conditions, the improvement which comprises effectingsaid treatment in the presence of boron fluoride.

5. A continuous process for the manufacture of high anti-knock gasoline,which comprises subjecting under pressure a normally gaseous hydrocarbonstream containing isoparafiins and olenes to the catalytic action of acatalyst comprising concentrated sulfuric acid and 'boron iiuoride in analkylation reaction zone to produce normally liquid hydrocarbons boilingin the gasoline range, withdrawing from the alkylation reaction zone ahydrocarbon-catalyst emulsion, recycling back to the said alkylationreaction zone said hydrocarbon-catalyst emulsion, separating overheadfrom the emulsion of said hydrocarbons and catalyst in said alkylationreaction zone vaporized hydrocarbons including a portion of the propanepresent in said reaction zone, collecting, compressing, cooling andcondensing the vaporized hydrocarbons, passing a portion of thecondensed hydrocarbons to a fractionating zone for removal of propane inexcess of that required Vto maintain a propane concentration of lessthan 10.0% by volume in said alkylation reaction zone, separatelywithdrawing from said reaction zone liquid hydrocarbons containingreaction products and catalyst, 'passing said liquid hydrocarbons to aseparation zone wherein the said catalyst is separated from thehydrocarbons, fractionally distilling the liquid hydrocarbons containingreaction products to obtain a fraction rich in isobutane, mixing saidfraction rich in isobutane with the portion of the condensedhydrocarbons from which excess propane has been removed and with theremaining portion of the condensed hydrocarbons from which propane hasnot been removed, and passing the said mixture to said alkylationreaction zone.

CECILIO L. OCON.

ERNEST A. OCON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS\-

